Problem 1: A uniform meter stick has a 60.0 g mass placed at the 20 cm mark. A pivot is placed at the 42.5 cm mark and the mass of the meter stick
20
4225
30
is 125g
At which mark on the meter stick do you need
60g
to attach a 50-g mass so it remains horizontal
in static equilibrium? (You must draw a force
diagram)

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90